An Analysis of Scientific Research Trends in Oral Implantology Between 2016 - 2022.

The present study aims to evaluate the trends of oral implant-related research in design and topics between the range of 2016 to the end of 2022. The electronic search was conducted in MEDLINE via Pubmed. Papers published in Clinical Oral Implant Research, Clinical Implant Dentistry and Related Research, International Journal of Oral Implantology and previously, European Journal of Oral Implantology, International Journal of Oral and Maxillofacial Implants, and Journal of Oral Implantology, Between January 1, 2016, to December 30, 2022, were retrieved. Articles were classified according to their study design and major subjects. The Joinpoint regression model was used to determine changes in the trends of study designs and topics. Statistical significance was defined as a p-value < 0.05. A total of 3,382 articles were analyzed in this study. In the specified period, in vivo, prospective cohort, retrospective case-control, randomized clinical studies, in the design; and prosthetic complications, peri-implant hard tissue studies, in the topic, experienced a significant decreasing pattern in the number of published articles as well as the total number of articles. Case reports and series, retrospective cohort, non-randomized clinical studies, in the design; and outcomes of implant-related treatment plans, immediate implant placement, peri- implantitis, in the topic, experienced a significant decreasing pattern followed by a significant increasing pattern with a turning point between 2017 to 2020. Considering the limitations of this scientific topical trends analysis, it can be concluded that the recent pandemic affected the research path in oral implantology in many ways.

Time management in multistep periodontal and implant treatments: a practical guide.

In addition to the proper selection of techniques, appropriate treatment sequencing and prioritization are prerequisites for successful periodontal and implant procedures. The aim of this study was to provide evidence-based time frames for various procedures pertaining to periodontal and implant treatment. A literature review was conducted to collect data on tissue healing; in areas in which data were lacking, the viewpoints of experienced clinicians were solicited to establish a consensus. This review reports recommended time frames for the healing processes associated with surgical crown-lengthening procedures (both functional and esthetic), fresh socket management, alveolar ridge management, soft tissue management, sinus floor augmentation, implant loading, and peri-implant defect management.

Potentials of pure xenograft materials in maxillary ridge augmentation: A case series.

Many patients require edentulous ridge augmentation for dental implant placement. The main objective of this study was to evaluate the results of maxillary edentulous ridge augmentation exclusively with xenograft materials with and without simultaneous sinus floor elevation. This study reports the data retrieved from the records of 16 patients. The treatment outcome was assessed at least 6 months, postoperatively. Paired samples t-test or Wilcoxon Signed Rank test was used to compare the pre-and postoperative ridge dimensions. Dental implants were placed simultaneously in 7 patients, while 9 patients underwent delayed implant placement. In total, 68 implants were placed, and 12 patients also underwent maxillary sinus floor augmentation. A significant bone gain was achieved in both horizontal and vertical dimensions of edentulous maxillary ridges (P < 0.001). Ridge width increased by an average of 4.35 ± 1.90 mm (95% CI: 3.84 to 4.85 mm) while ridge height in areas of sinus floor augmentation increased by 8.19 ± 2.91 mm (95% CI: 7.33 to 9.05 mm). Within the study limitations, it appears that maxillary ridge augmentation according to the guided bone regeneration (GBR) protocols with exclusive use of xenograft particulate materials can provide optimal bone quantity for dental implant placement.

Comparison of the Volume and Histological Properties of Newly Formed Bone after the Application of Three Types of Bone Substitutes in Critical-Sized Bone Defects.

This study aimed to compare the volume and quality of the newly formed bone following application of two types of xenografts and one synthetic material in bone defects in rabbit calvaria from histological and micro-CT aspects. Four 8-mm defects were created in 12 rabbit calvaria. Three defects were filled with bone substitutes and one was left unfilled as the control group. The newly formed bone was evaluated histologically and also by micro-CT at 8 and 12 weeks after the intervention. The percentage of osteogenesis was comparable in histomor-phometric assessment and micro-CT. Histological analysis showed that the percentage of the newly formed bone was 10.92 ± 5.17%, 14.70 ± 11.02%, 11.47 ± 7.04%, and 9.45 ± 5.18% in groups bovine 1, bovine 2, synthetic, and negative control, respectively after 8 weeks. These values were 33.70 ± 11.48%, 26.30 ± 18.05%, 22.92 ± 6.30%, and 14.82 ± 8.59%, respectively at 12 weeks. The difference in the percentage of the new bone formation at 8 and 12 weeks was not significant in any group (P > 0.05) except for bovine 1 group (P < 0.05). Micro-CT confirmed new bone formation in all groups but according to the micro-CT results, the difference between the control and other groups was significant in this respect (P < 0.05). All bone substitutes enhanced new bone formation compared with the control group. Micro-CT assessment yielded more accurate and different results compared with histological assessment.

In situ shell technique for edentulous ridge augmentation.

BACKGROUND: The novel two-stage technique presented in this study is based on guided bone regeneration for three-dimensional bone augmentation. METHODS AND RESULTS: The proposed technique was performed to augment an atrophic alveolar ridge in the maxilla and mandible. This method is based on using an autogenous bone plate, a mixture of allogeneic bone graft and injectable -platelet-rich fibrin, and a bioresorbable barrier membrane. Based on the cases presented in this study, sufficient osseous regeneration was achieved to place dental implants in an ideal position. CONCLUSION: Within the limitations of the present study, it seems that in situ shell technique could be a beneficial method to augment the extremely atrophied ridges with less morbidity and shorter operative time. KEY POINTS: Why is this case new information? The cases presented a new technique using in situ autogenous plates for ridge augmentation. What are the keys to the successful management of this case? The keys to the successful management of these cases are proper flap management and less traumatic bony plate preparation. What are the primary limitations to success in this case? The primary limitation to success in this technique would be a need for high surgical skills to conduct the procedure accurately.

Periodontal phenotype modification in orthodontic patients.

OBJECTIVE: The purpose of this study was to assess the feasibility of phenotype modification in orthodontic patients using combined bone and soft tissue grafting substitutes. CLINICAL CONSIDERATION: The surgical procedure was conducted on 18 patients (3 males, 15 females). Periodontal phenotype modification was conducted using demineralized freeze-dried bone allograft and a xenogeneic collagen matrix. The following parameters were recorded for each tooth at baseline and 12-month follow-up: O'Leary plaque index (PI), probing depth (PD), bleeding on probing (BOP), gingival thickness (GT), keratinized tissue width (KTW), gingival recession (GR), and vestibular depth (VD). The results showed a statistically significant increase in GT (2.02 ± 0.39 mm), KTW (1.11 ± 0.82 mm), and VD (0.18 ± 1.16 mm) (p < 0.05). GR was also significantly decreased (1.02 ± 0.99 mm) (p < 0.05). CONCLUSION: Within the limitation of this study, the proposed approach enhanced the periodontal condition in orthodontic patients. However, further studies with a larger sample size are needed to ensure long-term stability. CLINICAL SIGNIFICANCE: Hard and soft tissue conditions have paramount importance for long-term periodontal stability. Phenotype modification in orthodontic patients can diminish the probability of adverse consequences and result in optimal esthetic outcomes. The proposed technique using combined bone and soft tissue substitutes indicated promising results and could be recommended in orthodontic patients with thin periodontal phenotypes.

Coverage stability of peri-implant soft tissue dehiscence: A systematic review and meta-analysis.

OBJECTIVE: The occurrence of peri-implant soft tissue dehiscence, especially in the esthetic zone, can be challenging. This study sought to investigate how the passage of time affects the outcomes of treatment for peri-implant soft tissue dehiscence coverage. MATERIALS AND METHODS: A literature search was performed up to April 2023 via PubMed, Scopus, and Web of Science to retrieve studies reporting the data on peri-implant soft tissue dehiscence of at least 2-time points (baseline and follow-up). Clinical trials with a minimum of 5 participants, reporting at least 1 primary outcome, and with a minimum follow-up of 3 months were included. The primary outcomes were the changes in dehiscence depth, complete coverage, and mean coverage at different time points. RESULTS: Seven studies with 112 participants and 119 implants were included. Dehiscence depth increased insignificantly between 3 to 6 months. Although the dehiscence depth increased from 6 to 12 months in the tunnel group, it decreased in the coronally advanced group, and a slight decrease was observed from 12 to 72 months. Soft tissue thickness was the predictor for soft tissue margin stability. However, no significant relationship was found between the baseline dehiscence depth and complete coverage. CONCLUSIONS: Within the limitations of this study, it seems prudent to wait at least 6 months to achieve a stable soft tissue margin. CLINICAL SIGNIFICANCE: The occurrence of peri-implant soft tissue dehiscence, especially in the esthetic zone, can be a challenging complication. It is important not only to achieve coverage but also to ensure that the treatment results remain stable in the long term, in order to satisfy both patients and clinicians. A reasonable approach would be to wait for at least 6 months to achieve a stable soft tissue margin.

Sterility and bioactivity evaluation of two types of bone graft substitutes after removing the original packaging.

Background: Xenograft and allograft bone substitutes are widely used to replace the missing bone in defects. Since removing the packaging of these grafts can nullify their sterilization, this study aimed to evaluate the sterility and bioactivity changes of an allograft and a xenograft following uncapping/recap. Methods: Two types of commercial allograft and xenograft vials were unpacked and further exposed to operating room air, where implant surgery was performed for one second, ten minutes, and one hour. After three repetitions, samples were analyzed using microbiological tests and scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX) for sterility and bioactivity evaluation. Results: None of the bone graft samples showed microbial growth or bioactivity-negative changes after seven days of unpacking the vials. Conclusion: Despite the positive results of this study, future studies and more analysis considering influential factors are required. Also, disinfection and air exchange must still be observed during biomaterial application and bone grafting procedures.

Peri-Implant Tissue Health and Disease in the Pre- and Post-Loading Phases.

Considering the widespread use of dental implants, a precise definition for peri-implant tissue health and an appropriate classification for peri-implant diseases are imperative for researchers and dental clinicians. However, absence of a unanimous definition and an efficient classification system has created controversies in the published reports regarding the epidemiology and prevalence of peri-implant diseases. Moreover, lack of a standard system for differentiation of different grades of peri-implantitis further complicates the interpretation of reports regarding the diagnosis prevalence, treatment, and outcome of such conditions, and highlights the need for a classification system based on the severity of disease. Almost all of the currently available classification systems focus on the assessment of health or disease status of the tissues around loaded implants. The purpose of the present study is to propose a classification/scoring system for peri-implant tissue health before and after prosthetic loading. This grading system can aid the researchers and dental clinicians in assessment of peri-implant tissue condition both before and after prosthetic loading of dental implants.

Explantation Site Management: A Decision Algorithm for Re-Implantation.

Dental implants are currently the preferred choice to restore function and esthetics. Nonetheless, explantation is sometimes inevitable in cases with advanced bone loss, implant fracture, or improper implant position. This study aimed to propose an algorithm for reimplantation at sites of previous failure. There is limited evidence on the replacement of failed implants, most of which are case reports or clinical trials with a small number of patients. To the best of the authors' knowledge, this is the first study proposing a clinical-decision algorithm to help clinicians manage implant failures with new implants. There are a variety of reasons contributing to implant failure: The etiologic factor of failure and the morphology of the residual defect have paramount importance on implant removal techniques and subsequent treatment modalities. There is no consensus on a distinct protocol to replace failed implants. However, the clinicians and patients should know that placing a new implant in an area with a history of failure, regardless of early or late implant failure, may have a lower survival rate.

Short-term and long-term success and survival rates of implants supporting single-unit and multiunit fixed prostheses: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Whether placing implants to replace each missing tooth or using implant-supported fixed partial dentures provides better outcomes is unclear. PURPOSE: The purpose of this systematic review and meta-analysis was to assess the success and survival rates of implants supporting single-unit and multiunit fixed prostheses by using conventional protocols for placement and loading in short- and long-term follow-ups. MATERIAL AND METHODS: An electronic search was conducted in PubMed, Scopus, and Web of Science for studies published up to March 17, 2022. Comparative studies that reported the success or survival rates of both single-unit and splinted multiunit prostheses were considered for qualitative and quantitative analyses. RESULTS: A total of 68 publications comprising 11 271 implants were included. Compared with the single prostheses, the splinted multiunit group showed no significant differences in implant success rates in the short-term (risk difference=-0.004; 95% confidence interval (CI)=-0.033 to 0.025; P=.780) and long-term (risk difference=0.003; 95% confidence interval (CI)=-0.029 to 0.034; P=.874) follow-ups. Significant statistical differences were also not found in terms of the survival rates of the 2 groups (short-term risk difference=-0.004; 95% CI=-0.031 to 0.023; P=.779, long-term risk difference=-0.002; 95% CI=-0.029 to 0.025; P=.887). CONCLUSIONS: Implants supporting single-unit or splinted multiunit prostheses seem to be a predictable treatment in terms of survival and success over short and long periods. Nonetheless, it seems that cantilever and nonsplinted multiunit prostheses should be used with more caution.

Immediate implant placement in compromised sockets: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Immediate implant placement provides a popular therapeutic option. However, compromised sockets may jeopardize the treatment outcome. PURPOSE: The purpose of this systematic review and meta-analysis was to investigate the treatment outcome in terms of the implant survival rate and success parameters of immediate implant placement in compromised extraction sockets. MATERIAL AND METHODS: An electronic search was conducted in PubMed, Embase, Cochrane Library, and ISI Web of Science up to January 2021. Studies evaluating implant survival rate and main success parameters were included for a qualitative and quantitative analysis (risk ratio and mean difference). RESULTS: In total, 43 studies with analysis of 4825 sockets were included. Compared with the noncompromised sockets, the compromised group showed no significant differences in implant survival rates (risk ratio=0.992; 95% confidence interval (CI)=0.979 to 1.005; P=.246). No significant statistical differences were found in marginal bone level at ≤12 months (mean difference [MD]=0.033; 95% CI=-0.012 to 0.078; P=.154) or esthetic parameters. CONCLUSIONS: Immediate implant placement in compromised sites does not appear to decrease the survival and success rates. However, randomized clinical trials with large sample sizes should be conducted to draw a definite conclusion about the efficacy and safety of this treatment protocol in compromised sockets.

Biological reactions of dental pulp stem cells cultured in presence of new xenograft bone substitutes from different sources: An in vitro study.

Aims: This study aimed to compare the biological reactions of dental pulp stem cells (DPSCs) cultured on new xenograft bone substitutes derived from camel and bovine bones. Materials and Methods: DPSCs were cultured and placed on different xenograft materials including Bone Plus (bovine), Camel Bone, and demineralized bovine bone matrix. The viability and proliferation of cells were evaluated by the methyl thiazolyl tetrazolium assay after 24, 48, and 72 h. The alkaline phosphatase (ALP) test and Alizarin red staining were performed at 7 and 21 days to assess the osteoblastic differentiation of cells. Osteocalcin (OCN) gene expression was evaluated qualitatively at 3-, 7- and 14-days using polymerase chain reaction (PCR). Semi-quantitative PCR was also performed using ImageJ software. Data were analyzed by ANOVA and Tukey's honestly significant difference test. Results: The cell proliferation rate was significantly different among the three xenograft bone substitutes at 24-, 48- and 72 h (P < 0.05). The ALP activity of DPSCs in all three xenograft bone substitute groups was greater than that in the control group (P < 0.05). Alizarin red staining showed no significant difference in the formation of calcified nodules among the groups. Qualitative and semi-quantitative PCR displayed that the expression of OCN gene in the Camel Bone and Bone Plus groups was higher than that in the demineralized bovine bone matrix group. Conclusions: The Camel Bone xenograft caused a high proliferation rate and optimal osteogenic differentiation of DPSCs qualitatively and semi-quantitatively in vitro. Further studies are required on this xenograft bone substitute.

A systematic scoring system to determine the long-term prognosis for severely damaged teeth.

Many of the criteria commonly considered in treatment planning for severely damaged teeth are well known to clinicians. However, a systematic approach to decision-making is lacking. The purpose of this article is to introduce a quantitative systematic risk assessment scoring system (RASS) to determine the long-term prognosis for severely damaged teeth based on several important factors. Before any treatment decision is made, the dentist should take into account the role of systemic parameters such as the medical condition of the patient, smoking status, psychological factors, patient expectations with regard to the duration and overall cost of treatment, and periodontal health. In the assessment of local factors, emphasis should be placed on 5 parameters: crown to root ratio, root condition, risk of furcation involvement, complexity of the final restoration, and esthetic results. In the proposed RASS, each of these parameters is ranked using 4 color-coded levels of risk: optimal (green), favorable (blue), unfavorable (yellow), or hopeless (red). The presence of even 1 parameter in the red zone is sufficient to consider tooth extraction. If no parameter is in the red zone, the final decision should be made after the possible effects of all of the clinical conditions are weighed and the overall risk of treatment failure is determined. Clinical decision-making with regard to the preservation or extraction of severely damaged teeth is a challenging, multifactorial process. The RASS introduced in this article focuses on 5 main factors to simplify and organize the decision-making process; however, many other parameters may affect the final treatment decision. Moreover, no decision-making system can be definitively applied to all clinical scenarios, and the entire process depends on the knowledge, experience, and expertise of the clinician.

CBCT Evaluation of the maxillary palatine process as a donor site for the regeneration of periodontal defects.

Background: The maxillary palatine process (MPP) is an excellent source of autogenous bone transplants for anterior maxillary reconstruction. This research aimed to determine the quantity and quality of accessible MPP as a donor location. Methods: Cone-beam computed tomography (CBCT) scans of patients referred to the School of Dentistry were evaluated by a certified examiner. The harvestable MPP was defined as the space between the distal surfaces of maxillary first premolars. OnDemand 3D Imaging software was used to determine bone properties. SPSS software was used to investigate the following variables: Bone characteristics are correlated with age and gender, accessible volume, and palatal width and height. P<0.05 was defined as the level of statistical significance. Results: This study was performed on CBCT scans of 81 subjects (41 females and 40 males). MPP volume and palatal heights were 1.33±0.53 cm3 and 20.86±5.51 mm, respectively. Maximum bone density was observed around lateral incisors. Palatal width was 33.81±2.42 mm between canines and 41.81±2.66 mm between premolars. The MPP volume was significantly greater in males (P<0.001). Additionally, there was a positive correlation between the volume and palatal width (P<0.05). Conclusion: Within the constraints of this research, there is a limited supply of MMP accessible for use as a graft source, and it is best suited for treating localized bone lesions. The favorable link between palatal breadth and harvestable volume aids the surgeon in estimating the quantity of bone accessible during the first evaluation.

A comparison of human dental pulp stem cell activity cultured on sandblasted titanium discs decontaminated with Er:YAG laser and air-powder abrasion: an in vitro study.

Decontamination of implant surfaces is important to the treatment of peri-implantitis. Er:YAG laser and air-powder abrasion system are regarded as the most effective means of decontamination of implant surfaces. The aim of this in vitro study was to compare the activity of human dental pulp stem cells (hDPSCs) cultured on decontaminated sandblasted titanium discs using Er:YAG laser irradiation and air-powder abrasion. Forty-five titanium discs were contaminated with Escherichia coli (E. coli) bacteria and fifteen titanium discs served as sterile control groups. Thirty contaminated titanium discs were decontaminated with Er:YAG laser or air-powder abrasion system and fifteen contaminated discs were used as contaminated control group. Afterwards, hDPSCs were seeded on all sixty experimental titanium discs. The effects of two decontamination tools on hDPSCs viability were evaluated by MTT assay. Alkaline phosphatase (ALP) activity assay, quantitative real-time PCR analysis and alizarin red staining method were performed to assess hDPSCs osteogenic differentiation. Scanning microscope electron (SEM) was also used to evaluate the effects of two different decontaminated methods on cellular morphology. Our study showed that decontamination using Er:YAG laser caused maximum cell viability. However, the ALP activity was not different in laser and air-abrasion groups. The significant expression of an osteoblastic marker and stronger Alizarin red staining were observed in laser irradiation groups. In addition, SEM observation indicated that grown cells were more stretched and more filopodia in Er:YAG-treated discs. In the present study, Er:YAG laser and air-powder abrasion improved the activity of the cells cultured on the decontaminated titanium discs. However, in comparison with air-powder abrasion, Er:YAG laser was more effective.

Effects of Two Protocols of Low-Level Laser Therapy on the Proliferation and Differentiation of Human Dental Pulp Stem Cells on Sandblasted Titanium Discs: An In Vitro Study.

Introduction: Stem cell activities have different effects on tissue response and its outcomes. Low-level laser therapy (LLLT) can be considered a trigger to modify stem cell activities. The objective of the present experimental investigation was to study the effects of two protocols of LLLT on the proliferation and differentiation of human dental pulp stem cells (hDPSCs) cultured on sandblasted titanium discs. Methods: Cells obtained from human dental pulp were seeded/cultured on titanium discs and were set in 2 main groups: (i) Radiated cells using the gallium-aluminium-arsenide (GaAlAs) diode laser at a continuous wavelength of 808 nm at 3 J/cm2 for 12 sec or 5 J/cm2 for 20 seconds, and (ii) Non-irradiated cells serving as control groups. The impact of LLLTs on hDPSC-proliferation and viability was investigated using the MTT assay after 24, 72 and 96 hours. The alkaline phosphatase activity was studied with p-nitrophenylphosphate after 14 and 28 days. The ability of hDPSCs to express osteocalcin was investigated using real-time polymerase chain reaction after 28 days, while their attachment was observed under a scanning electron microscope (SEM) after 14 and 28 days. Results: Our study showed that LLLTs caused maximum cell proliferation in 96 hours (P<0.001) with 3 J/cm2 resulting in a higher proliferation rate. The highest activity of alkaline phosphatase and osteocalcin expression was observed in the laser radiation groups after 28 days. Conclusion: The outcomes of the current study showed that cultured hDPSCs on sandblasted titanium discs had a tendency towards increased cellular activity in response to LLLTs. Thus, LLLTs could regulate the activities of hDPSCs on bone repair surrounding the sandblasted titanium discs.

Clinical and Radiographic Outcomes of a Novel Transalveolar Sinus Floor Elevation Technique.

Objective: The aim of this study was to evaluate the clinical and radiographic outcomes of the "vertically expander screw" (VES) technique as a novel approach for maxillary sinus floor elevation and simultaneous implant placement. Materials and Methods: Forty-four patients (26 females, 18 males) received 71 implants with simultaneous transalveolar sinus floor elevation via the VES technique. The threaded bone expanders were used to elevate the sinus floor as well as bone expansion. The patients were followed-up on a regular basis, and final clinical and radiographic examinations were performed at least 24 months following functional loading. Statistical analysis was conducted using the Chi-square test, the correlation coefficient, and the independent t test (p < 0.05, 95% confidence interval). Results: All implants showed successful osseointegration. The mean marginal bone loss (MBL; 0.38 ± 0.75 mm) at the site of premolars was not significantly different from the value at the site of molars (0.17 ± 0.50 mm). The mean intrasinus bone gain (IBG) was not significantly different (3.47 ± 1.22 mm and 4.11 ± 1.67 mm, respectively; p = 0.92). Evaluation of implant success index (ISI) score revealed no difference between the premolars and molars (p = 0.12). Conclusion: Despite the limitations of the present study, it seems that the VES technique and simultaneous implant placement in carefully selected cases may result in promising outcomes. Clinical Relevance: Insufficient alveolar bone height and poor bone quality often complicate implant placement in the edentulous posterior maxilla. The VES technique and simultaneous implant placement can bring about favorable clinical and radiographic outcomes and high survival rate in carefully selected cases.

Influential Factors in Buccal and Lingual Plate Perforation around Dental Implants Using Cone-Beam Computed Tomography.

This study determined the influential factors in buccal and lingual plate perforation around dental implants using cone-beam computed tomography (CBCT). In this retrospective, cross-sectional study, CBCT scans of dental implants taken for purposes not related to this study from 2017 to 2018 were retrieved from the archives of a private dental clinic. Demographic information, implant site, length, diameter, shape, and angulation, buccal and lingual plate thickness, buccolingual diameter of bone, and presence of crestal bone resorption were all assessed on CBCT scans. Data were analyzed using chi-squared, Mann-Whitney, Kruskal-Wallis, and independent t-tests. Of 604 implants, 88 had caused bone perforation in 41 females (46.6%) and 47 males (53.4%) with a mean age of 54.97 ± 13.99 years; 83% of perforations were in the maxilla; 55.7% of implants causing perforation were cylindrical and 44.3% were conical. The mean length and diameter of implants was 11.78 ± 1.91 mm, and 4.49 ± 0.76 mm, respectively; 38.9% of perforations were in the buccal and 18.2% in the lingual plate, and 42% were in the apical region. Crestal bone loss was noted in 58% of perforation cases. The mean angular deviation of implants was 19.13 ± 12.41°. Implant length and diameter had a significant association with the occurrence of perforation in the mandible (P < 0.05). Perforations had a higher frequency in the posterior maxilla, and mainly in the apical region. The buccal plate was thin in the anterior maxilla, with minimum thickness in the apical region. Lingual plate perforation had the highest frequency in the mandible.

Morphological Variations of the Posterior Mandible: Proposing a Classification for Ridge Morphology Based on Cone-Beam Computed Tomography Data.

This study sought to assess the morphological variations of the posterior mandible and propose a classification for ridge morphology based on cone-beam computed tomography (CBCT) data. This retrospective, cross-sectional study evaluated 130 CBCT scans of patients with edentulous mandibles. Qualitative variables including lingual and crestal concavity, vertical, horizontal and angular limitations, and ridge morphology were assessed at 631 sites on CBCT scans of 87 males and 43 females. A classification for ridge morphology in the posterior mandible was proposed based on the collected data. The kappa coefficient was calculated to assess the intra-observer agreement, and data were analyzed using the chi-square test and Pearson's correlation test. The frequency of lingual concavity increased from the anterior towards the posterior region relative to the mental foramen (P < 0.05). The maximum frequency of lingual concavity (11.1%) was noted at 21 mm distance from the mental foramen while its minimum frequency (4.1%) was noted at 5 mm from the mental foramen (P < 0.05). Ridge morphology, defined as ridge angulation < 15°, no lingual or crestal concavity, no limitation in width, and 8-10 mm height, had the highest frequency. Its suggested treatment plan included a 10-mm implant without width limitation or severe angulation. The majority of common morphologies had no width limitation with ridge angulation < 15°. Height limitation was only present in two of them, which can be resolved by placement of a short implant or ridge augmentation.